People think of massage therapy as a “safe” therapy, and of course it mostly is. But things can go wrong, or at least a bit sour. While serious side effects in massage therapy are extremely rare, minor side effects are downright common. A 2007 survey of 100 massage patients found that 10% of 100 patients receiving massage therapy reported “some minor discomfort” in the day following treatment. This would mainly be a familiar slight soreness that is common after a massage, known as “post-massage soreness and malaise” (PMSM) — and I’m surprised only 10% reported it. The massages they were getting must have been quite gentle.
Interestingly, 23% reported unexpected benefits that had nothing to do with aches or pains. (Benefits for musculoskeletal problems were not documented.)
This study is underpowered. It cannot and does not rule out rare and/or serious side effects of massage therapy, which do exist. You could probably do several studies of 100 patients without encountering a single nasty situation. But what if you surveyed 1,000 patients? Or 10,0000? Massage is not completely safe — what is? — and other adverse effects would almost certainly turn up in a big enough survey. Nevertheless, according to one of alternative medicine’s most vigorous critics, Dr. Edzard Ernst, “Serious adverse events are probably true rarities.” And yet, reviewing the literature again in 2013, Ernst and Posadzki found at least 18 reported examples of “moderately severe” reactions to normal massage, especially of the neck.
When massage goes bad
So what could possibly go wrong? Massage can…
directly cause new injuries (mostly quite minor, but not all)
aggravate existing injuries and chronic pain problems
distract patients from more appropriate care
mildly stress the nervous system
And don’t forget, of course, that pointlessly draining your wallet is another kind of pain. If someone spends $5,000 on massage therapy that has only a minor therapeutic effect, or none at all, is that an “injury”? It’s an insult, at the least!
In my decade (2000–2010) as a massage therapist, I met many patients who had been harmed by massage therapy to some degree — fortunately, mostly just expensive disappointments and minor backfires, but quite a few more serious cases too.
A painful, alarming sensory experience can actually dial up pain sensitivity — even long term. Furthermore, vulnerability to this awful phenomenon is much more common and significant in desperate patients who already have chronic pain — so they seek and tolerate intense therapy.
The experience of pain is affected by many factors, including emotional and psychological ones. People in chronic pain usually experience some degree of pain neurology dysfunction, and a breakdown of the relationship between how bad things feel and how much is really wrong. That breakdown can be seriously worsened by threatening sensations. Thus, people experiencing pain system dysfunction can have minor and major setbacks in response to excessively painful massage.
One of my readers suffered this kind of disaster. She was injured by “fascial release” therapy, a style which is often too intense and may focus on treating connective tissues to the exclusion of considering the patient’s comfort and nervous system.
I may have been too aggressive with a few patients over the years. I never did serious harm this way as far as I know, but I’m sure that I occasionally did more harm than good. This failure was due entirely to my ignorance of pain science: despite being an unusually well educated massage therapist, I simply did not know that an intense massage could change pain sensitivity itself. Does your therapist?
Poisoned by massage
Excessive pressure probably has another predictable outcome: a light poisoning. Seriously.
For example: an 88-year old man collapsed the day after an unusually strong 2-hour session of massage therapy.7 He had too much myoglobin in his blood, and it was poisoning his kidneys and generally making him feel rotten. It’s not a sure thing that his condition was cause by the massage — but it is quite likely. It is almost certainly a perfect example of one of those rare but serious complications of massage. Another case study comes up below.
Ironically, many people believe that massage is a detoxification treatment, but in fact it’s probably the opposite.
Post-massage soreness and malaise is probably caused by mild rhabdomyolysis (“rhabdo”): poisoning by the waste products of injured muscle.
True rhabdo is a medical emergency in which the kidneys are poisoned by myoglobin from muscle crush injuries. But many physical and metabolic stresses cause milder rhabdo-like states — even just intense exercise, and probably massage as well. There are many well-documented cases of exertional or “white collar” rhabdo, and there is a strong similarity between PMSM and ordinary exercise soreness. A rhabdo cocktail of waste metabolites and by-products of tissue damage is probably why we feel a bit cruddy after all biological stresses and traumas — including massage, sometimes.
PMSM is just an unavoidable mild side effect of strong massage. And for a few more vulnerable patients, it could actually be a little dangerous.
Getting on your nerves
Nerves aren’t nearly as vulnerable to pressure as people generally think — most of them can actually take quite a licking and keep on ticking without a single symptom — but they aren’t invulnerable. Push hard enough in the wrong place, and you can injure a nerve, of course. In a 2017 incident, a woman’s radial nerve was crushed by an aggressive massage in her upper, inner arm. It’s rare, but it happens.
And I once caused such a nerve injury myself: it was a minor injury, but it did — augh — result in weeks of aggravating discomfort for my client.
The Archives of Physical Medicine & Rehabilitation reported a similar spinal accesory nerve injury: “a rare and illustrative case of spinal accesory neuropathy associated with deep tissue massage leading to scapular winging [the shoulder blade sticking out] and droopy shoulder as a result of weakness of the trapezius muscle.”
In a word, pay more attention to the massage when you take it as an arm pain relief.